The application relates to an apparatus for handling and placing foundation devices, and/or pipes, and/or augers, into the ground
Apparatuses for driving/pile-driving or rotationally driving foundation devices and pipes, or for drilling, are known. These apparatuses are available as separate implements, which may be self-propelled, comprising all of the necessary guides (holding and orientation functions) and drives. As such, they may be appropriate for their intended purposes and very convenient, but they are comparatively complex, in particular because, each of them can be only employed for use as part of a specific placement process, for example, for pile-driving, or drilling, or rotational driving. They are only cost-effective where a large number of similar placement processes must be performed on an ongoing basis.
Users who have only occasional need would consider such apparatuses only if they were in the form of attachments, which are attachable to known multifunctional construction vehicles, such as to the boom of an excavator. For this type of user, they are economical only in this way. Such an accessory unit is described in U.S. Pat. No. 6,942,430 B1 as an apparatus for placing pipes by way of rotational movement.
With the known apparatus, however, it is in fact difficult to maintain the desired driving direction, be it the perpendicular or at another desired angle, throughout the entire rotational driving process.
This is partially due to the fact that, as the rotational driving process progresses, the boom on which the rotational driving apparatus is mounted is lowered. The coupling point of the rotational driving tool at the boom follows a circular line about the pivot axis of the boom on the excavator. This means that, at the upper end, the rotational driving tool and the pipe or post to be rotationally driven-in thereby, or the auger, follows the coupling point, and unless a correction is made, the device will be displaced out of the intended direction, in the direction of extension of the excavator arm.
A similar faulty alignment occurs in the lateral orientation when the longitudinal axis of the pipe to be rotationally driven-in does not coincide with the movement plane of the excavator arm, for example because the excavator, and consequently the boom, are skewed when the rotational driving direction is perpendicular, or in cases where, while the excavator may be sitting straight, the rotational driving direction differs from the perpendicular is not aligned perpendicularly. Combinations of this error and the above-described error may result in excursion errors in the pipe that is to be driven-in rotationally, in each direction.
In addition, further sources of error include resistance in the ground, which displaces the pipe to be driven-in rotationally out of the intended alignment, and finally also operating errors on the part of the driver of the construction vehicle, such as, in particular, those which may occur when attempting to correct the above-described faulty alignments.
In the prior art, the above-described misalignments are compensated for primarily by way particular steering of the construction vehicle and/or the boom, and specifically by way of the driver moving the construction vehicle forward or back, depending on the situation, or rotating the vehicle, or shortening, extending or pivoting the boom.
This procedure, however, includes considerable inherent opportunity for error since the manner and the extent of the correction depend on the visual judgment of the operator and the precision of their steering movements, and also, perhaps in combination, the technology (precision of the steering control device). It is apparent that this kind of precision will often be inadequate, in particular in driving movements in rough terrain, and in light of the implements that are involved.
A partial solution to these problems is provided in U.S. Pat. No. 3,746,104. There, the length of a drilling boom can be hydraulically adjusted. This eliminates directional corrections by way of driving the construction vehicle forward and in reverse, which would otherwise be required, for example, so as to prevent the coupling point from drifting out of the longitudinal axis of the drilling device when the boom is lowered. In other words, the necessary correction is carried out by hydraulically changing the length of the boom, rather than by driving movements which are difficult to control.
However, this partial solution only solves the problem of faulty alignments in the direction of extension of the boom. For instance, if the boom is at an angle other than a right angle with respect to the placement direction of the drill, any change in the length of the boom will also be associated with a change in height. Depending on the direction of the movement, this will result in the drill being undesirably pulled out, or pushed in. In this situation, other faulty alignments must also be compensated for by corresponding driving movements of the excavator, and possibly by pivoting movements of the excavator body. In some instances, it may not be possible to compensate for them at all. This solution is, above all, highly complex because it requires a completely different boom from that which is commonly used.
A different partial solution to the problem is set forth in AT 387 424 B, which combines the gimbal mounting of a drilling apparatus with the capacity to adjust the length thereof hydraulically so as to thereby prevent movements of the boom and associated problems.
However, this solution only prevents problems resulting from movements of the boom. The document does not offer any solutions for other faulty alignments requiring readjustment of the apparatus. Again, the only option that remains is to readjust by way of the driving movements of the construction equipment or control movements of the boom.
In addition, this apparatus is also highly complex, and cannot readily be considered as an option for long foundation devices/pipes/augers, because these require a boom height which is usually not available for use with conventional construction vehicles.